docs: def unpadding(s, bs=AES.block_size):
      """Reverse operation to padding (see above).
  
      Parameters
      ==========
  
          :param s: bytes-like object;
          :param bs: encryption block size.
      """
  
      if PY3:
          return s[:s[-1] - 96] if len(s) % bs == 0 else ''
      else:
          return s[:ord(s[-1]) - 96] if len(s) % bs == 0 else ''